MUC1 and small cell lung carcinoma: To determine whether the MUC1–PP2A axis functions across other SCLC subtypes, we investigated phosphorylation levels of PKCζ and NUMB in cell lines representing distinct subtypes–NCI‐H69 (SCLC‐A), NCI‐H526 (SCLC‐P) and NCI‐H82 (SCLC‐N).